The present invention relates to a fluid apparatus such as a bellows type pump, a diaphragm type pump, or an accumulator.
As a pump for circulating and transporting chemical liquid in various processes such as washing of surfaces of ICs or liquid crystal display devices in a semiconductor producing apparatus, used is a bellows type pump or a diaphragm type pump in which no particles are generated as a result of the pumping operation (for example, Japanese Patent Application Laying-Open No. 3-179184). In a pump of this kind, pulsations are produced by reciprocal motion due to extension and contraction of the bellows. In order to reduce the pulsations, therefore, also an accumulator is used (for example, Japanese Patent Application Laying-Open Nos. 6-17752 and 10-196521).
In such a bellows type pump, a diaphragm type pump, and an accumulator, in order to prevent the performance of processing such as washing from being lowered, it is requested to reduce staying of the transported liquid and always supply fresh liquid. In a bellows type pump, an accumulator, or the like, particularly, a suction port of the pump or an inflow port of the accumulator is opened so as to eject sucked liquid or inflowing liquid into a liquid chamber in a direction parallel to the axial direction (direction of reciprocal motion) of a respective bellows. Therefore, the liquid easily stays in an extending and contracting portion of the respective bellows, and contamination tends to occur. In the case where liquid containing a sedimenting material such as slurry of silica or the like is used as a polishing solution for Chemical Mechanical Polishing (CMP) of a semiconductor wafer, a hard disk which is to be incorporated into a computer, and the like, the sedimenting material easily sediments and aggregates in a pump or an accumulator to affect the life of the pump or the accumulator.
The invention has been conducted in order to solve the problems. It is an object of the invention to provide a fluid apparatus in which staying of liquid in a pump or an accumulator is reduced to enable fresh liquid to be always supplied, and, even in the case where liquid containing a sedimenting material such as slurry is used, the sedimenting material can be prevented from sedimenting and aggregating inside the pump or the accumulator.
The fluid apparatus of the invention is a fluid apparatus configured by a reciprocating pump in which a diaphragm that reciprocally moves in an axial direction, such as a bellows or a diaphragm is disposed in a pump body so as to form a liquid chamber with respect to an inner wall of the pump body, a suction port and a discharge port are disposed in the inner wall of the pump body facing the liquid chamber, and a stroke of sucking liquid from the suction port into the liquid chamber, and a stroke of discharging the liquid in the liquid chamber from the discharge port are alternately performed by reciprocal motion of the diaphragm. In the fluid apparatus, the suction port is disposed so as to eject the sucked liquid toward a circumferential wall which is in the liquid chamber and in a direction different from the axial direction.
In this case, the suction port may be disposed in a side face of a protruding tip end portion of a suction check valve which is fixed so as to protrude into the liquid chamber from the inner wall of the pump body facing the liquid chamber.
In the thus configured reciprocating pump, since the suction port is disposed so as to eject the sucked liquid toward the circumferential wall in the liquid chamber, the sucked liquid ejected from the suction port produces a swirling flow along the inner periphery of the liquid chamber, and the interior of the liquid chamber is stirred by the swirling flow. Therefore, staying of liquid in the liquid chamber is reduced to enable fresh liquid to be always supplied, and, even in the case where liquid containing a sedimenting material such as slurry is used, the sedimenting material can be prevented from sedimenting and aggregating in the liquid chamber.
The fluid apparatus of the other invention is a fluid apparatus configured by an accumulator in which a diaphragm that reciprocally moves in an axial direction, such as a bellows or a diaphragm is disposed in an accumulator body so as to form a liquid chamber inside the diaphragm and an air chamber outside the diaphragm, an inflow port and an outflow port are disposed in an inner wall of the accumulator body facing the liquid chamber, and a liquid pressure in the liquid chamber balances with an air pressure in the air chamber. In the fluid apparatus, the inflow port is disposed so as to eject inflowing liquid toward a circumferential wall which is in the liquid chamber and in a direction different from the axial direction.
In this case, the inflow port may be disposed in a side face of a protruding tip end portion of a discharge check valve which is fixed so as to protrude into the liquid chamber from the inner wall of the accumulator body facing the liquid chamber.
In the thus configured accumulator, since the inflow port is disposed so as to eject the inflowing liquid toward the circumferential wall in the liquid chamber, the inflowing liquid ejected from the inflow port produces a swirling flow along the inner periphery of the liquid chamber, and the interior of the liquid chamber is stirred by the swirling flow. Therefore, staying of liquid in the liquid chamber is reduced to enable fresh liquid to be always supplied, and, even in the case where liquid containing a sedimenting material such as slurry is used, the sedimenting material can be prevented from sedimenting and aggregating in the liquid chamber.